Total sum of age of 80 students of the class = 15 X 80 = 1200 years
15 students → 15 X 16 = 240 years
25 students → 25 X 14 = 350 years
Sum of 40 students = 590 years
Total age of remaining 40 students = 1200 – 590 = 610
So, average age = 15.25 years
